Marine propulsion apparatus



Nov. 7, 1961 c. w. F. HAMILTON 3,007,305

MARINE PROPULSION APPARATUS Filed Sept. 2, 1958 2 Sheets-Sheet 1 l n ventor G If FHmmbZton A ttorneys 1961 c. w. F. HAMILTQN 3,007,305

MARINE PROPULSION APPARATUS Filed Sept. 2, 1958 2 Sheets-Sheet 2 I nvenlor A ttorne ya United States Patent This invention relates to marine propulsion apparatus of the type comprising a rearwardly directed jet orifice connected to pumping means adapted to take in water from outside a boat or the like vessel with which said marine propelling means is associated in use and discharge a jet of water into the air or under water from said jet orifice in a manner such as to drive the boat or the like vessel.

At present to provide means for causing the boat with which marine propulsion apparatus of the type described is associatedin use to go astern, some form of deflecting apparatus is interposed in the path of the jet issuing from the jet orifice so that the jet is redirected in the required direction. With this arrangement there is considerable turbulence, e.g. due to the fact that the water being redirected is flowing at considerable velocity.

It is, therefore, an object of the present invention to provide control means for controlling the motion of a boat having marine propulsion apparatus of the type described which will obviate or minimise the foregoing difiiculty.

Accordingly the invention consists in control means for controlling the motion of a boat having a marine propulsion apparatus of the type described, said control means comprising a control member and mounting means therefor, said control member being so shaped and mountable that it can be interposed in the path of the water discharged by the pumping means to redirect the path of said water while the latter is still under pressure head generated by the pumping means, to cause the boat with which said control means is associated to go astern, and it can be removed completely from the path of the discharging water to allow the water to propel said boat forwardly.

It is a further object of the present invention to provide marine propulsion apparatus of the type described incorporating control means as above set forth.

One preferred form of the invention will now be described with reference to the accompanying drawings, in which:

FIGURE 1 is a diagrammatic side elevation of a boat, shown in part only, incorporating marine propulsion apparatus of the type described incorporating the present invention,

FIGURE 2 is an enlarged view of the control means forming part of the present invention in the position for forward propulsion,

FIGURE 3 is as FIGURE 2 but with the control member shown in a closed position, and

FIGURE 4 is a further view of FIGURE 2 showing the control member in its position in which it performs the dual function of redirecting the path of the water to cause the boat to go astern and providing a discharge orifice smaller than the rearwardly directed orifice for discharge of the redirected water.

In the preferred form of the invention a pumping means for a marine propulsion apparatus of the type described is constructed and comprises an outer casing 1 for an axial flow multi stage preferably two stage pump. The inlet 2 to the pump is enlarged as compared with the pump casing and is arranged so that when the shaft 3 of the pump is arranged substantially horizontally but F 3,007,305 Ice Patented Nov. 7, 1961 2 preferably sloped slightly downwardly towards the stern 4 of the boat (shown in part only) and with which the unit is associated in use, the inflow to the pump is disposed so as to be adapted to'dra-w water through the bottom of the boat.

The pump shaft 3 extends forwardly through suitable bearings 5, stufling boxes 6 and'the other usual appertenances to a suitable coupling 7 whereby the pumpmay be driven by a motor 8. It is to be appreciated that the pump casing 1 is curved at 9 from the water inlet to the pump so that the water passes through an angle of appreaching while travelling between the inlet and the pump. The two pump impellers 10 and the interstage baffles are constructed according to standard practice and suitable priming and other ancillary means are provided in the known way. The connection 11 is provided between the pump body and the circular jet nozzle or orifice 12-. Situated adjacent the jet orifice so as to control the flow of water therefrom, are control means which, as shown, are situated immediately'aft of the jet orifice. The control means comprise a shaped gate valve member 14 and mounting means are provided to mount the member adjacent the orifice 12 but on the downstream side thereof, comprising suitable slide ways 15 in which the gate valve member 14 slides in a substantially water tight manner. The member 14 is so shaped and mountable that it can be interposed in the path of the 'water discharging by the pump to perform the dual function of redirecting the path of the water while the latteris still under the pressure head generated by the pumping means to cause the boat to go astern, and providing a discharge orifice smaller than the rearwardly directed orifice 18 for the discharge of the redirected water. 7

To this end the member 14 has a concavity 17 and, when the member is interposed to perform the above dual function as shown in FIGURE 4, the concavity 17 is arranged so that the part 17a is within and the part 17b is without the passageway beyond the jet orifice through which the water passes from the pump. The effect of this arrangement is to cause the path of the water to be redirected as shown by the arrowed lines 19 in FIGURE 4 while the water is still under the pressure head generated by the pump, that is to say before the water pressure is reduced to atmospheric pressure and the energy given to the water by the pump transformed into velocity.

In addition the control member 14 has a portion 20 adapted to blank oil a part of the terminating passageway lat the orifice 20 in a substantially water tight manner.

The use of the foregoing construction is as follows. As is shown in FIGURE 2 the control member 14 is raised out of the way, and is removed from the path of the discharging water. The water from the pump then passes through the passageway 21 and is discharged from the jet orifice 18 for propelling the boat 24 forwardly. Steering apparatus shown in outline at 25 is provided to deflect the issuing jet in the known way. The control member 14 is then movable from the foregoing position shown in FIGURE 2 in which there is a predetermined maximum area of the jet orifice to the position shown in FIGURE 3 in which there is a complete closure of the jet orifice. In other words the control member is movable to substantially completely stop the flow of water from the pump. It is to be understood that the control member when in this position substantial-1y seals the jet orifice l8 and consequently the outlet from the pump. When the control member is moved to the position shown in FIG- URE 4, that is to say the position in which it performs the above mentioned dual function, the flow of water is redirected by the concavity as shown by the arrowed lines 19 and the redirected water is discharged through a discharge orifice 1 7c which is smaller than the rearwardly directed jet orifice 18. Because the water is redirected while still under the pressure head generated by the pump there is less turbulence of the water and the discharging jet is more effective. We have found that a much better reversing effect is given by the construction than by other constructions.

We have also found that the provision of a multi stage preferably two stage axial flow pump develops the necessary pressure head to drive a boat at high speeds. This is an advantage which is not in a single stage axial flow pump which do not develop suitable pressure heads for such speeds.

What I claim is:

1. Control -means for controlling the motion of a marine vessel having a hull provided with a main discharge oi'ifice and pumping means connected to the main discharge orifice through a substantially straight conver-gent passageway for discharging water as a propulsive jet through such main discharge orifice, said control means including a mounting means on the hull adjacent the main discharge orifice, a single valve member supported by said mounting means downstream of said main discharge orifice and movable progressively to and from positions fully opening the main discharge orifice, fully closing the main discharge orifice and diver-ting the water discharged from the main discharge orificethrough a substantially water-tight passage formedthereby to an auxiliary orifice, said auxiliary orifice being of substantially :smaller maindischarge area than the discharge orifice and :facing in substantially the opposite direction tov the main orifice a part of said valve member defining the lower edge of said auxiliary orifice when said valve member is in the position diverting the Water to the auxiliary orifice, and the lower edge of said valve member being above the lower edge of said main discharge orifice when said valve member is in the position fully opening the main orifice with said substantially straight convergent passageway offering no obstruction to the discharging water when the main discharge orifice is fully open for reducing efficiency in forward travel.

2. Control means as claimed in claim 1, in which said mounting means comprises a pair of opposed slides mounted in substantial parallelism, and said valve memher being a plate slidably mounted in said opposed slides and provided with a forwardly facing concavity forming part of the wall of the water-tight pasage.

3. Control means as claimed in claim 1, in which said pumping means is an axial flow pump, steering means and the valve member being a shaped plate slidably mounted and vertically movable in the mounting means and being disposed between'the main discharge orifice and the steering means, with the steering means being effective when the valve member is in the fully open position.

References Cited in the file of this patent UNITED STATES PATENTS Water Jet Propels Boat. 

